Emotion Dynamics in Reciprocity: Deciphering the Role of Prosocial Emotions in Social Decision-making

To date, the relevance of prosocial emotions in social decisions based on reciprocity remains poorly understood. Expected and experienced emotions in interoceptive-social dimension, expected offers, and actual acceptance were measured in 476 participants during an ultimatum game consisting of fair, moderate, and unfair offers. We investigated whether participants adjust social decisions according to prediction errors on prosocial emotions and reciprocity. Participants’ acceptance trajectories were explained by prediction errors in dominance, valence, and reward. Participants were categorized into 4 distinct subgroups based on their patterns of reward expectation, acceptance, and emotional experiences before and after the offer. Furthermore, the relationships between prosocial emotions, social decisions, and reciprocity varied across these subgroups. This study’s measurement and analysis of multidimensional trajectories across four affect dimensions reveal that social decisions are influenced by the responder’s perception of partner’s reciprocity, as well as by the subsequent prediction error of basic and prosocial emotion.